Unitary rigid wire connectors and method of making wire connections



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S. N. BUCHANAN ETAL UNITARY RIGID WIRE CONNECTORS AND METHOD OF MAKING WIRE CONNECTIONS March 8, 1966 Filed Aug. 1, 1951 ATTORNEY March 1966 s. N. BUCHANAN ETAL 3,239,796

UNITARY RIGID WIRE CONNECTORS AND METHOD OF MAKING WIRE CONNECTIONS 2 Sheets-Sheet 2 Filed Aug. 1, 1961 INVENTORS m r zziz z BY ma/ 10K ATTORNEY United States Patent Filed Aug. 1, 1961, Ser. No. 131,958 7 Claims. (til. 33997) This invention relates to electrical wire connectors and connector assemblies and systems for coupling a plurality of selected multi-connector assemblies together; and more broadly to the method of electrically connecting a plurality of wires of substantially the same size to a common unitary rigid pressure connector.

The object is to simplify and improve the performance of multiple terminal blocks and connectors and to make them foolproof against the possibility of making poor connections at some terminals, or of loosening the connections by vibration or shocks by using a new method of wire connection with a rigid one piece connector.

A further object is to provide a simple, sturdy terminal connector having a reduced size slot for receiving oversize wires to provide maximum pressure Contact of said wires with a conducting material in at least one side of said slot by pushing away a restricted portion of the insulation, if any, on the Wire adjacent said contact as the wire is pushed into said reduced size slot, and forcing a substantial surface of the bare wire against said conducting material to form a good electrical contact joint between the wire and the conducting material, which is reliable and vibration proof, occupies a minimum of space, and re quires but a single pressure stroke to wedge each wire in said slot.

A further object is to provide a simple wire connector means for receiving one or more wires, each of which requires but a single pushing stroke for installation in said connector to invariably form a good pressure contact joint therewith without requiring prestripping of any insulation on said wires, and without weakening the wires at their contact joints, while supporting said wires at opposite sides of said joints if necessary to prevent accidental oscillations of said wires causing flexure at said joints to weaken them.

A further object is to provide a simple but sturdy construction of a connector unit which will receive a plurality of wires having a reasonable range of wire sizes, in a pair of parallel slots in the spaced prongs of a U-shaped strip of conductive material set in a rectangular pocket in the face of a block of insulating material, which reenforces the prongs against accidental spreading of the slots so that if an oversize wire is inserted in the slots, it will be flattened at the four points of contact with the opposite sides of the two slots, instead of spreading the slots.

A further object is to provide slots in the opposite sides of the above mentioned block in line with the slots in the prongs for snugly receiving an insulated wire and guiding it into the rounded outer ends of the prong slots.

A further object is to extend the block slots to the inner ends of the prong slots, and to provide a hand tool for pressing a wire into the slots so that the insulation of an insulated wire will be automatically pushed off the wire only at the four points of contact with the sides of the prong slots.

A further object is to provide block assemblies having male plug units extending from the bottom of the block for use in stacking a plurality of blocks to couple two or more selected multi-connector assemblies, and for interchanging ditferent connector assemblies in a system of circuits.

Other and more specific objects will become apparent in the following detailed description of typical assemblies of connectors made in accordance with the present invention and illustrated in the accompanying drawings, wherein:

FIG. 1 is a side elevation view of an assembly of multiconnector blocks mounted on a base board, showing an independent block assembly adapted for stacking into one of the blocks on the base board,

FIG. 2 is an enlarged sectional view taken on the line 22 through the stacking block in FIG. 1,

FIG. 3 is .a similarly enlarged sectional View taken on the line 3-3 through the base board block in FIG. 1,

FIG. 4 is a similarly enlarged plan view of the base board block taken at 4-4 in FIG. 1,

FIG. 5 is an end view of a stacking block showing a modified form of handle attachment,

FIGS 6 to 10 show a preferred form of tool which may be used for installing a Wire in the block having U-shaped connector units.

The conventional screw-type wire connectors have been found to be inadequate for use in many cases where space is at a premium or where costs of labor and material are too high and where the safety factor is of paramount consideration. The present invention provides a type of rigid pressure connectors which performs all the functions of the screw-type better, at a considerable saving in cost of labor, time and materials as well as space requirements, and with a higher factor of safety against failures to make and hold a good pressure contact indefinitely. It is furthermore impossible for a careless workman to make a poor connection. One single pushing stroke is all that is required to make a uniformly perfect pressure contact of the wire in the connector unit.

The basic structure of the present connectors has been found to be the simplest and requires no separable part or resilience for providing the pressure contact by any adjustment or resilience between the parts, as is required in the prior art. The one piece rigid conductor slot wall or pin, as the case may be, automatically pushes through only the portion of the insulation on an insulated wire, necessary to flatten the corresponding bare wire surfaces against or between its conductor sides or around the pin respectively, when the wire to be connected is pushed into the slot or over the pin, and maintains ample contact pressure at this point of flattening to cause no restriction to the electrical current that may be passed through this contact. This pressure, by proper design of the connector, may be made suflicient to frictionally hold the connection against movement between the contact surface or loosening of the connection 'by continuous vibration or shocks. Additional retaining means may be provided where necessary to insure against such loosening in extreme vibrational or shock environments.

A wire inserting tool may be used for pushing a wire down into the slots of any one of the U-shaped connector units in the blocks of the type shown in FIGS. 1 to 5. The wire 24 to be inserted is placed in the 'outer end of the corresponding prong slots 12.

The inserting blade 14 of the tool 15 has a groove 16 in its outer end for placing over this wire and extends over the entire width of the block 18, the portions 20 of this blade being reduced in thickness to slide freely between the sides of the respective slots in the block 18, the unreduced outer portions 21 slide freely at the sides of the block and guide the tool blade so that its out out slits 23 register with prong slots 10, so as to provide clearance for pieces of the insulation which are pushed off the wire by the connector prong ends 26.

As the wire 24 is pushed into the slots with this tool blade 14, the oppositely curved outer ends 26 of the sides of the prong slots 12 push the insulation-on an insulated wire off only at the four contact points of the wire with the sides of the prong slots of the connector unit 28, the remaining insulation automatically providing a seal for these four contact points. The sizes of wires that may be used in any size of prong slots may range from the width of the slot to several thousandths of an inch thicker, because the over size wires will not be weakened in the insertion process but will merely be flattened, retaining substantially the same cross-sectional area at the contact points as they had before insertion. The adjacent portions 30 of the wire outside the prong slots are held by the block slots 12 against sharp bending of the wire at the contact joints when either end of the wire 24 is pulled about the corresponding joint.

A range of wire sizes from No. 18 to No. 24 was found to work well in a single size of prong slots, showing no detectable drop in voltage across any of hundreds of connections tested.

The wire is not weakened in the insertion process but is merely flattened to the thickness equal to the width of the prong slots used. The flattened contact areas provide ample pressure surface contact with the sides of the prong slots to cause no restriction in the cross section of the electrical path across the connection, because the four points of contact provide a total positive contact area between the wire and the connector unit approximately equal to the Wire cross-section.

This type of connection is not subject to loosening by shocks or continuous vibrations, because the flattened portions are held against displacement of the wire in the slots under great pressure, substantially equal to that required to flatten the wire. The only way to remove the wire is to pull it up out of the slots, and it may be used over again in the same connector unit in the same position or in any other in the same unit or in another unit of the same size.

The blocks 18 may be made with base flanges 32, and may be of suitable length to accommodate any desired number of connector units. These blocks may be mounted on a base board 34 by means of stud screws 36. Any number of such block assemblies may be mounted on a base board. Washer strips 38 may be used under the screw heads between adjacent blocks mounted end to end.

The screws 36 may be bored to provide guideways for guide pins 40 fixed in a plug-in block assembly 42. Block assembly 42 has the same arrangement of connector units as block 18', but in addition, two pairs of male plug prongs 44 extending downwardly from the bottom of the block, are connected by rivets 46 to each connector unit 28. The male plug prongs straddle any wires that might be inserted in the corresponding connector unit when the assembly 42 is plugged into the block assembly on the base board, each pair of prongs, shaped substantially as shown, being biased outwardly against the inside of the opposite prongs of the corresponding connector unit 28.

The male plug prongs 44 may be made unitary with the corresponding connector units 28 instead of being riveted thereto, as shown in FIG. 35, by having each pair of the male plug prongs 44 extend from an extension 47 from opposite sides of the base of the U-shaped connector unit 28.

The block assembly 42 may be provided with a handle 48 to facilitate its handling. This handle 48 may be pivoted in the ends of the block, for swinging it out of the way when changing some of the connections, or for stacking additional blocks that might be plugged into the blocks below them for multi-circuit connections. These additional blocks may be provided with similar guide pins 40 fitting into guide bores that may be drilled in the lower blocks.

Instead of pivoting in' the block, the ends of the handle 48 may be removably insertable into grooves 50 in the ends of the block, as shown in FIG. 5.

We claim: j

1. A wire connector unit comprising at least two blocks of insulating material each having a plurality of rectangular shaped recesses therein, each said block having aligned slots extending through the block on opposite sides of each recess, said slots being of a size for receiving the insulated wires to be connected by the connector, a connector element of conductive material fitted snugly into each recess and having two spaced upstanding wire engaging portions each having a slot therein aligned with the slot in the insulating block opening into the recess through the wall against which the respective wire engaging portion lies, said slots in said wire engaging portions having a width slightly less than the diameter of the conductor portion of the smallest size of wire to be accommodated by said wire connector unit, a plurality of male plug prongs depending from one of said blocks and in electrical connection with the respective upstanding wire engaging portions in the respective recess of said one block, guide pins depending from said one block, and the other block having guide bores therein into which said guide pins extend for guiding said one block into engagement with said other block with the male plug prongs on the one block in electrical contact with the upstanding wire engaging portions in the recesses of the said other block.

2. A wire connecting unit as claimed in claim 1 in which said male plug prongs each comprise two pairs of prong members with the prong members of each pair being spaced a distance substantially equal to the spacing between the upstanding wire engaging portions in the slots into which the prongs are adapted to extend, the direction of the spacing of the prong members in each pair being the same as the spacing of the wire engaging portions, whereby one prong member engages each wire engaging portion in the recess into which the prong members extend when the blocks are in engagement, the pairs of prong members being spaced transversely of the direction of alignment of the slots so that they lie on opposite sides of a wire engaged in said wire engaging portions.

3. A wire connecting unit as claimed in claim 2 in which said prong members and said wire engaging portions in the said one block are integral with each other, said one block having an aperture opening out of the bottom of the block from said recess through which said prong members extend.

4. A wire connecting unit as claimed in claim 2 in which each said wire connector element further comprises a base lying in the bottom of the recess and extending between said wire engaging portions, and said male plug prongs each further comprise a base extending between said prong members, and a rivet extending through said one block in the bottom of each recess and connecting said base of said wire connector element to the base of said male plug prong.

5. A wire connecting unit as claimed in claim 1 in which at least said one block has a stiff wire handle pivoted thereon to facilitate handling of the blocks.

6. A wire connecting unit as claimed in claim 1 in which said other block has hollow bores therethrough, securing members extending through said bores for securing said block to a supporting surface, said securing members in turn having therein said bores for receiving said pins on said one block.

7. In combination, a wire connector unit comprising a block of insulating material having at least one substantially rectangular shaped recess therein, said block having aligned slots extending through the block on opposite sides of said recess, said slots being of a size for receiving the insulated wires to be connected by the connector, and a connector element of conductive material fitted snugly into said recess and having a base corresponding in shape to the bottom of the recess and lying on the bottom of the recess, and having an upstanding wire engaging portion at each end of said base against the walls of the recess having said slots therein, said upstanding wire engaging portions each having a slot therein aligned with the slot in the insulating block opening into the recess through the wall against which the respective upstanding wire engaging portion lies, said slots in said wire engaging portion having a width slightly less than the diameter of the conductor portion of the smallest size of wire to be accommodated by said wire connector, and a means for forcing a wire into said connector unit having a blade having a length greater than the dimension of the block in the direction of the alignment of said slots, a groove in a longitudinal edge of said blade adapted to be placed over the wire to be inserted into the connector unit, said blade having two pairs of opposed grooves the grooves in each pair being on the opposite faces of said blade and the pairs of grooves being spaced a distance equal to the opposite sides of the recess in said block, the thickness of the blade between the grooves in each pair being only slightly less than the width of the slots in said block, and said blade having transverse slots therein between said pairs of grooves and spaced at distance equal to the spacing of said upstanding wire engaging portions.

References Cited by the Examiner UNITED STATES PATENTS 2,333,266 11/1943 Miller 339-95 2,680,235 6/1954 Pierce 339276 2,688,123 8/1954 Benham et al 339176 2,802,083 8/1957 Lapeyre 33999 X 2,888,660 5/1959 Fox 339-176 3,012,219 12/1961 Levin et a1. 33998 FOREIGN PATENTS 615,737 1/ 1949 Great Britain. 266,481 1/ 1950 Switzerland.

JOSEPH D. SEERS, Primary Examiner. 

1. A WIRE CONNECTOR UNIT COMPRISING AT LEAST TWO BLOCKS OF INSULATING MATERIAL EACH HAVING A PLURALITY OF RECTANGULAR SHAPED RECESSES THEREIN, EACH SAID BLOCK HAVING ALIGNED SLOTS EXTENDING THROUGH THE BLOCK ON OPPOSITE SIDES OF EACH RECESS, SAID SLOTS BEING OF A SIZE FOR RECEIVING THE INSULATED WIRES TO BE CONNECTED BY THE CONNECTOR, A CONNECTOR ELEMENT OF CONDUCTIVE MATERIAL FITTED SNUGLY INTO EACH RECESS AND HAVING TWO SPACED UPSTANDING WIRE ENGAGING PORTIONS EACH HAVING A SLOT THEREIN ALIGNED WITH THE SLOT IN THE INSULATING BLOCK OPENING INTO THE RECESS THROUGH THE WALL AGAINST WHICH THE RESPECTIVE WIRE ENGAGING PORTION LIES, SAID SLOTS IN SAID WIRE ENGAGING PORTIONS HAVING A WIDTH SLIGHTLY LESS THAN THE DIAMETER OF THE CONDUCTOR PORTION OF THE SMALLEST SIZE OF WIRE TO BE ACCOMMODATED BY SAID WIRE CONNECTOR UNIT, A PLURALITY OF MALE PLUG PRONGS DEPENDING FROM ONE OF SAID BLOCKS AND IN ELECTRICAL CONNECTION WITH THE RESPECTIVE UPSTANDING WIRE ENGAGING PORTIONS IN THE RESPECTIVE RECESS OF SAID ONE BLOCK, GUIDE PINS DEPENDING FROM SAID ONE BLOCK, AND THE OTHER BLOCK HAVING GUIDE BORES THEREIN INTO WHICH SAID GUIDE PINS EXTEND FOR GUIDING SAID ONE BLOCK INTO ENGAGEMENT WITH SAID OTHER BLOCK WITH THE MALE PLUG PRONGS ON THE ONE BLOCK IN ELECTRICAL CONTACT WITH THE UPSTANDING WIRE ENGAGING PORTIONS IN THE RECESSES OF THE SAID OTHER BLOCK. 